amino acid homeostasis

Pseudoscientific theories vs transgenerational transmission

The neurobiological consequence of predating or grazing (January 2013)

“The patterns of synaptic connections perfectly mirror the fundamental differences in the feeding of P. pacificus and C. elegans“, Ralf Sommer concludes. A clear-cut result like that was not what he had necessarily expected.

Transgenerational transmission of environmental information in C. elegans (April 21, 2017)
Editors summary:

Ancestral legacy effects

Environmental change can critically affect the lifestyle, reproductive success, and life span of adult animals and their for generations. Klosin et al. showed that in the nematode worm Caenorhabditis elegans, exposure to high temperatures led to expression of endogenously repressed copies of genes—sometimes called “junk” DNA. This effect persisted for >10 generations of worms. The changes in chromatin occurred in the early embryo before the onset of transcription and were inherited through eggs and sperm.

My summary: They linked energy-dependent thermodynamic cycles of protein biosynthesis and degradation to the feedback loops that link food odors and pheromones to the physiology of biophysically constrained changes in chromatin and chromosomal inheritance via supercoiled DNA, which links angstroms to ecosystems in all living genera.
Reported as: Environmental ‘memories’ passed on for 14 generations
Ben Lehner’s group predicted that gain-of-function mutations might contribute to differences in phenotype. See also:
3D structures of individual mammalian genomes studied by single-cell Hi-C (2017)
Differential DNA mismatch repair underlies mutation rate variation across the human genome (2015)
Predicting phenotypic variation in yeast from individual genome sequences (2011)
Parallel evolution of conserved non-coding elements that target a common set of developmental regulatory genes from worms to humans (2007)
No experimental evidence of biologically-based cause and effect suggests that anything but natural selection for energy-dependent codon optimality will ever link the biodiversity of yeast to nematodes and humans.
See: System-wide Rewiring Underlies Behavioral Differences in Predatory and Bacterial-Feeding Nematodes as cited in Nutrient-dependent/pheromone-controlled adaptive evolution: a model

Clearly, however, the epigenetic effects of food odors and pheromones are involved in neurogenic niche construction as exemplified in nematodes (Bumbarger, Riebesell, Rödelsperger, & Sommer, 2013), and in flies (Swarup et al., 2013).

Differences in the behavior of nematodes are determined by nutrient-dependent rewiring of their primitive nervous system (Bumbarger et al., 2013). Species incompatibilities in nematodes are associated with cysteine-to-alanine substitutions (Wilson et al., 2011), which may alter nutrient-dependent pheromone production.

The honeybee is currently an accepted model organism of nutrient-dependent pheromone-controlled adaptive evolution of the brain and behavior that is consistent with what is known about neurogenic niche construction in nematodes (Bumbarger et al., 2013).


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